Pneumatic gun



A.. CHRISTIE.

PNEUMATIOGUN.

APPLICATION man MYI. 1919.

SHEETS 1,396,929. Pate jNov. 15,1921.

A. CHRISTIE. RNEUMATIC GUN. .APPLICATION FILED MAY I, I9I9.

2 SHEETS-SHEET 2.

'Jara/V701@ l @Vm-M@ i reciprocated by-an air or. other pressure UNITED sra'rwis "PwjrEN'r ori-ica4 Annahmen onmsrtn, Orsenna, Wnsnve'ron.

PNEUMATIC GUN. i

'o all 'whom t may concern: p Be it known that I,`ALEXANDER CHRISTIE,

`a citizen of the United States, residing at #of which the following is aspecification.

This invention relates to an improvement in pneumatic gunsfor riveting and simllar purposes, wherein a. drlver 1s aut0mat1cal1y i current under control of the operator, and

3 which driver` imparts a blow to a bit formed i for the desired work.

In pneumatic guns `of this` type, las ordii narily constructed the outward or working `movement of thebit is resisted by the work,

and should the tool `loe removed from th e "work, without `proper air control, the bit is liable to be forced entirely from the gun. In some uses, as in `ship building or the like, such result might involve the loss of the bit.

The present invention is therefore, chiefiy directed to means, which may be associated with any appropriate gun of this type, and which will prevent the loss of the bit by limiting its outward stroke, such limit being,`

however, beyond the normal working stroke.

A further object` is the association` with such limiting means, of bit-holding members, serving to retain the bit in such limit position; and, further the disposition of such holding members in such relation to the Working stroke of the driver, that the bit, when so held, permits the driver to advance to a position to close the driver-return pressure port, and hence the driver is held at rest, and hammering of the bit avoided.

In the drawings Figure 1 is a plan view, illustrating the ap lication of my improvement.

ig. 2 is an end `elevation of the same. i

`Fig.`3 is a section on line 3-3 Fig. 2.

Fig. 4 is a detail showing the gun-carried hin e member of the attachment in place.

'me improvements are applicable to any gun of this type, and as the details of such gun, aside from the particulars hereinafter noted, are relatively unimportant, as conventional gun is here illustrated, comprising a body 1, having a longitudinal bore 2, to receive a driver 3, and a bit 4. The gun is or may be operated by compressed air, admitted from a suitable source through an in- 'Patented Nov. 1'5, 1921.

i i Application `led lay 1, 1919. Serial No. 298,983.

let 5, o ening into the bore 2, in advance of the c osed end G of saidbore.v A stop 7 limlts movement of the driver toward the :inletl 5, to prevent said driver closing the 1nlet. A by-pass 8 leads through the body, opening into the bore at appropriate points, as 9 and 10, so `that thedriver maybe rapidly reeiprocated` under the necessary `air pressure to impart the desired successive blows to the bit. p

The present improvement is more particularly concerned` with an attachment for the gun to prevent accidental loss ofthe bit, and the device comprises a sleeveelike member, made up of two sections 11 and 12, pivotally connected through interfitting ears 13, to the respective edges of a pivot block 14, secured to the body` 1, adjacent the operative endithereof. The `gun body is formed with an annular recess 15, and the sections 11 and 12 provided with corresponding rib 16, to fit in said recess when assembled. The sections are locked in closed relation and to the gun body, by a spring strip 17, secured at one end to one section, and provided adjacent its free terminal with a locking lug 18 to engage a depression 19 in the other section of the device, to lock the sections together. A button 20, mounted in one section overlies the free end of the spring strip, to'release the lock in an obvious manner when desired.

The outer end of the attachment is disposed beyond the free end of the gun body 1, and the interior bore of such device is re.- duced beyond the end of the body, providing a limiting wall 21. The bit 4: is provided with an annular rib 22, of asize to engage the wall 21, in the extreme forward position of the bit, and thus prevent the complete se aration of the bit from the gun.

n use of course, the operative end of the bit is held against the work, and the disposition 0f the wall 21 is beyond the movement of the rib 22, in the working strokes of the bit. Hence, no contact of the rib and wall occ-urs during the working action of the bit, and yet when free of the work, the bit cannot bel driven from the gun under any circumstances.

It is also highly desirable that the hammering action on the bit by the driver be prevented when the bit is free of the work and air pressure through inadvertance not out oif. The present improvement provides for such a result, in arranging, within the bore `*of the device, beyond the end of the gun body, a series of spring fingers 23, se-

' cured to the sections of the device," and having appropriately formed holding terminals 24 arranged adjacent the limiting wall 21. Under the free drive of the bit, the rib 22 j' is moved 'into contact with the wall 21, and within the grip ofthe terminals 24 oi the fingers 23. The bit is thus frictionally held in such limit position bythe spring fingers. This limit position is beyond the usual working stroke,hence the driver will have been moved to a position to'close the port l0 from the by-pass .8, and the driver can receive no power for a return stroke.

- .l All parts are thus inactive, but are readily restored to normal operative positions by pressure on the operative end of the bit,

either by forcing such end against the work,

'erin any other appropriate manner. Having thus described the invention, what is claimed as new is Ina pneumatic tool the combination of a gun body provided with a central bore and 25- a port communicating at opposite ends with said bore, a hammer mounted in the bore andbeing ofsuch length as to be between the open ends of the port when in one position, a bit retaining member, the end wall ofv 30- Wliich is spaced from the end of the body to 'clining away from the end Wall of the body and terminating in a rebent end portion, the inner terminals of the rebent portions being 1n the path of movement of the iiange,

whereby when the pressure is exerted on the tool to operate same the fluid will be ad* mitted to reciprocate the hammer, movement of the latter in one direction positioning the fiange to one side oi' and out oicontact with the resilient members, and whereby it normal pressure on the tool be removed the hammer will be dra-Wn beyond one open end of the port and cut oif the iinid and will project the bit to force its flange beyond theJ rebent ends of the resilient inem bers and thereby hold the bit and the hammer in inactive position.

In testimony whereof I allix my signature.

ALEXANDER CHRISTIE. 

